Can't find smoke and color mapping options for Fluid Simulation Blender 2.9
I believe this was renamed to &quot;Grid Display&quot; after blender 2.90. See here for some usage info. Compare the docs between versions 2.83 and 2.91.
The Smoke settings Buoyancy Density, Buoyancy Heat and Vorticity are now labeled Gas, you can see them in your screenshot.